285 is the tyre width in millimetres, 55 is the sidewall height as a percentage of the width, and R20 means radial construction for a 20-inch wheel. Together, these measurements affect clearance, ride comfort and the overall rolling diameter. If your vehicle is specified for this size, stick to it and match the same ratings shown on your current tyres.
Start by checking the load index and speed rating printed on your existing tyre sidewall or on the vehicle placard, as heavier SUVs and pick-ups often require higher load capacity. Choose tyres that meet or exceed the manufacturer minimums, especially if you tow or carry regular loads. Once you have the correct ratings, you can compare brands and tread styles with confidence.
A highway tread is usually the best choice for mainly road driving, prioritising quieter running and predictable wet-road handling. An all-terrain tread can add bite on gravel, mud and grass, but it may be louder and can feel less sharp on tarmac. Pick the pattern that matches where you drive most, then narrow down by load rating and reviews.
Replacing in pairs is acceptable if the remaining two tyres are in good condition and the new tyres are fitted to the same axle, but the handling balance can still change. For many 4x4 and AWD vehicles, replacing all four is often recommended to keep rolling circumference and grip more consistent. If you replace only two, keep tread depths closely matched across each axle and follow your vehicle guidance.
The change increases both width and overall diameter slightly, which can affect clearance, steering feel and speedometer accuracy. It may also move you away from the manufacturer specification, which is important for handling and load capacity on heavier vehicles. Check your handbook or door sticker first, and only change size if you have confirmed it is approved for your exact model and wheel width.
